Life on Mars - Looking in all the Wrong Places?

Life on Mars may not Look Like we Expect

It's a question that has been asked over and over. It's also one of the main driving forces for exploring Mars and other planets and moons, like Titan and Europa.

Current theories, however, are based on one key condition: life elsewhere will be similar to what we have on earth.

Reasonable, right? But what if it's not true? Could life exist elsewhere, but not as we know it?

That’s what Washington State University planetary scientist Dirk Schulze-Makuch thinks. In a recent paper, he wrote:

If you don’t explore the various options of what life may be like in the universe, you won’t know what to look for when you go out to find it.

As an example, on Earth there is a species of beetle that excretes an explosive mix of hydrogen peroxide and other chemicals to ward off predators. As Schulze-Makuch says:

We do not propose that these organisms exist but like to point out that their existence would be consistent with physical and chemical laws, as well as biology.

On other planets, under gravity conditions similar to those present on Mars, a bombardier beetle-like alien could excrete a similar reaction to propel itself as much as 300 meters into the air.

Life on Mars

The landing site on Mars of Viking Lander 2, which operated on the planet surface for 1,316 days and was turned off in 1980 when its batteries failed. (Photo from Mary A. Dale-Bannister, Washington University in St. Louis)

Earth life, with its unique biochemical toolset, could feasibly survive on a Mars-like planet with a few novel adaptations.

First, organisms would need a way to get water in an environment that is akin to a drier and much colder version of Chile’s Atacama Desert. A possible adaptation would be to use a water-hydrogen peroxide mixture rather than water as an intracellular liquid, Schulze-Makuch said.

Hydrogen peroxide is a natural antifreeze that would help microorganisms survive frigid Martian winters. It is also hygroscopic, meaning it naturally attracts water molecules from the atmosphere.

During the daytime, plant-like microorganisms on a Martian-like surface could photosynthesize hydrogen peroxide. At night, when the atmosphere is relatively humid, they could use their stored hydrogen peroxide to scavenge water from the atmosphere, similar to how microbial communities in the Atacama use the moisture that salt brine extracts from the air to stay alive.

But detecting extraterrestrial life on Mars or elsewhere in the Solar System will be a challenge. It is likely that a robotic lander on Mars or Titan, two bodies where we have the best chance of finding life, would need a completely different suite of experiments than have been used to date to detect life. Even then we might not know what we’re looking for. But Schulze-Makuch is optimistic that there’s something out there. As he said:

I would be very surprised if there’s no life on Mars

But finding life on Titan may be more important. Mars is, comparatively speaking, very much like Earth, but Titan represents a completely different type of environment. And that’s possibly more important in answering whether life is abundant in the universe.

If you find life on Titan, then life can originate in different conditions, and is much more diverse than we probably ever expected.

In other words, if there is life on Titan, it could mean that life is much more abundant in the universe then we think.

On Earth, we have only scratched the surface of the physiological options various organisms have. But what we do know is astounding. The possibilities of life elsewhere in the universe are even more staggering.

Only the discovery of extraterrestrial life and a second biosphere will allow us to test these hypotheses, which would be one of the grandest achievements of our species.